1. Field of the Invention
The present invention relates to a foot support which will assist individuals with weakness or paralysis of dorsiflexion and eversion of the foot and extension of the toes, the condition commonly referred to as "foot drop." The foot support comprises a quilted cushioned center piece with a pouch affixed thereto for receiving the forward end of the foot of the user. On the sides of the cushioned center piece are two straps which will wrap around the leg of a user.
2. Description of the Background Art
Foot drop is characterized in a person who otherwise has sufficient muscular control to move his or her foot relative to the ankle in planar flexion (a downward pushoff motion), lacks sufficient muscular control to subsequently affect a dorsiflexion motion to raise the foot back up for the next step. Also, usually evidenced in a person's having foot drop is the diminished capacity to move the foot in what is termed eversion, or rotating the outer part of the foot in an upward manner.
Two central disorders of gait which can benefit from the instant foot support are gait hemiparesis and gait paraparesis. The hemiparetic patient typically stands and walks with the affected arm flexed and the leg extended. In walking, the patient has difficulty flexing the hip and knee, dorsoflexing the ankle and everting the foot. The paretic leg swings outward at the hip with the trunk rocking in the opposite direction to avoid scraping the toes of the foot on the floor. The leg rotates in a semicircle, first away from and then towards the trunk. This attempts to prevent the foot from scraping the floor which would cause the toe and inner side of the sole of the shoe to be worn first.
Similarly, the spastic paraparetic gait has some problem with walking as the hemiparetic patient, but bilaterally. Their steps are short but the patient rocks the trunk side-to-side trying to compensate for the inability to flex hips and stiff-leg movement. The feet scrape the floor; therefore, the soles of the shoe at the toes are immediately worn.
The common peroneal nerve is the continuation of a lateral trunk of the sciatic nerve which is derived from the posterior division of the vertical rami of spinal nerves L4, L5, S1 and S2 (primarily L4, L5, S1). This nerve usually separates from the sciatic nerve in the upper popliteal fossa (into the common peroneal nerve and tibial nerve). The common peroneal nerve descends downwardly and laterally in the popliteal fossa, passing behind the head of the fibula and winds obliquely around its neck. This nerve then pierces the superficial head of the peroneus longus muscle which forms a tendinous arch over the nerve (fibular tunnel) and as it emerges from the tunnel, it divides into two major branches (1) superficial peroneal (musculocutaneous) and (2) deep (anterior tibial), peroneal nerves. The deep peroneal nerve runs in the anterior compartment of the leg between the anterior tibialis and extensor hallucis muscles and tendons, which innervates the (1) anterior tibialis, (2) extensor hallucis brevis and longus, extensor digitorum longus and brevis and peroneus tertius muscles.
The function of each muscle innervated by the deep peroneal nerve is as follows. The anterior tibialis carriers out dorsiflexion of the ankle joint and inversion of the foot. When weakened, it decreases the ability to dorsiflex the ankle joint and allows a tendency towards eversion of the foot.
The extensor hallucis longus and brevis act to extend the metatarsophalangeal and interphlangal joints of the great toe. This assists in inversion of the foot and dorsiflexion of the ankle joint. If weakened, it will decrease the ability to extend the great toe and allows a position of flexion. The ability to dorsiflex the ankle joint is decreased.
The extensor digitorum longus and bevis act to extend the metatarsophalangeal joints and assist in extending the interphalangeal joints of the second through fifth digits and second through fourth digits. When weakened, it will decrease the ability to dorsiflex the ankle joint and evert the foot.
The peroneus tertius acts to dorsiflex the ankle joint and everts the foot. If weakened, it will decrease the ability to evert the foot and dorsiflex the ankle joint.
A complete lesion of the common peroneal nerve results in the classic foot drop, i.e. the inability of dorsiflexion and eversion of the foot and extension of the toes and a slapping gait. This disorder can be caused by strokes, spastic paraparesis, polio, amyotrophic lateral sclerosis, multiple sclerosis and parkinsonism. Peripheral causes of palsy of the common peroneal nerve are external compression, direct trauma, traction injuries, masses, entrapment, vascular, diabetes, leprosy, lumbosacral trunk injury, sciatic nerve injuries or neuropathies secondary to Guillian-Barre, toxic metabolic or alcohol.
While other prior art devices have attempted to address the problem of foot drop, there have been many drawbacks with these devices. Often they are bulky, heavy and cumbersome. Due to their weight, they will unnecessarily fatigue the user and will be uncomfortable. Some of these devices will excessively confine the leg and place limitations on the foot and ankle movement which tends to further reduce the remaining functional capacity of the patient. Therefore, these devices can hinder the patient's ability.
Some prior art devices cannot be used without professional aid. Also, many devices require orthopedic shoes or other specialized shoes. A user cannot walk barefoot or with sandals or slippers in such devices.
An additional drawback to many prior art devices is that they are visible such that they draw attention to the patient's problem. This is psychologically difficult for a user who is often self-conscious of his or her condition.
Many prior art arrangements require an excessive attachment arrangement. For older users who might have arthritis, these devices are unacceptable.
Accordingly, a need in the art exists for a simple and effective foot support which will assist individuals with weakness or paralysis of dorsiflexion and eversion of the foot and extension of the toes. This device should be easy to put on, lightweight and nonconspicuous.